There is a new book out by Brad Bowling and Jerry Heasley titled Mustang Special Editions. It covers the California Special, HCS, Ski Country Special, Pace Cars, etc. Interesting book covering alot of Special Editions from 64.5- present. It lists the registries for the cars and the related web page. I checked out www.limited600mustang.com and found alot of intersting information. Pick up a copy at your local book store.